src/librustc/mir/tcx.rs

   1 // Copyright 2015 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 /*!
  12  * Methods for the various MIR types. These are intended for use after
  13  * building is complete.
  14  */
  15
  16 use mir::*;
  17 use ty::subst::{Subst, Substs};
  18 use ty::{self, AdtDef, Ty, TyCtxt};
  19 use ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
  20 use hir;
  21 use ty::util::IntTypeExt;
  22
  23 #[derive(Copy, Clone, Debug)]
  24 pub enum LvalueTy<'tcx> {
  25     /// Normal type.
  26     Ty { ty: Ty<'tcx> },
  27
  28     /// Downcast to a particular variant of an enum.
  29     Downcast { adt_def: &'tcx AdtDef,
  30                substs: &'tcx Substs<'tcx>,
  31                variant_index: usize },
  32 }
  33
  34 impl<'a, 'gcx, 'tcx> LvalueTy<'tcx> {
  35     pub fn from_ty(ty: Ty<'tcx>) -> LvalueTy<'tcx> {
  36         LvalueTy::Ty { ty: ty }
  37     }
  38
  39     pub fn to_ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Ty<'tcx> {
  40         match *self {
  41             LvalueTy::Ty { ty } =>
  42                 ty,
  43             LvalueTy::Downcast { adt_def, substs, variant_index: _ } =>
  44                 tcx.mk_adt(adt_def, substs),
  45         }
  46     }
  47
  48     pub fn projection_ty(self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
  49                          elem: &LvalueElem<'tcx>)
  50                          -> LvalueTy<'tcx>
  51     {
  52         match *elem {
  53             ProjectionElem::Deref => {
  54                 let ty = self.to_ty(tcx)
  55                              .builtin_deref(true, ty::LvaluePreference::NoPreference)
  56                              .unwrap_or_else(|| {
  57                                  bug!("deref projection of non-dereferencable ty {:?}", self)
  58                              })
  59                              .ty;
  60                 LvalueTy::Ty {
  61                     ty: ty,
  62                 }
  63             }
  64             ProjectionElem::Index(_) | ProjectionElem::ConstantIndex { .. } =>
  65                 LvalueTy::Ty {
  66                     ty: self.to_ty(tcx).builtin_index().unwrap()
  67                 },
  68             ProjectionElem::Subslice { from, to } => {
  69                 let ty = self.to_ty(tcx);
  70                 LvalueTy::Ty {
  71                     ty: match ty.sty {
  72                         ty::TyArray(inner, size) => {
  73                             tcx.mk_array(inner, size-(from as usize)-(to as usize))
  74                         }
  75                         ty::TySlice(..) => ty,
  76                         _ => {
  77                             bug!("cannot subslice non-array type: `{:?}`", self)
  78                         }
  79                     }
  80                 }
  81             }
  82             ProjectionElem::Downcast(adt_def1, index) =>
  83                 match self.to_ty(tcx).sty {
  84                     ty::TyAdt(adt_def, substs) => {
  85                         assert!(adt_def.is_enum());
  86                         assert!(index < adt_def.variants.len());
  87                         assert_eq!(adt_def, adt_def1);
  88                         LvalueTy::Downcast { adt_def: adt_def,
  89                                              substs: substs,
  90                                              variant_index: index }
  91                     }
  92                     _ => {
  93                         bug!("cannot downcast non-ADT type: `{:?}`", self)
  94                     }
  95                 },
  96             ProjectionElem::Field(_, fty) => LvalueTy::Ty { ty: fty }
  97         }
  98     }
  99 }
 100
 101 impl<'tcx> TypeFoldable<'tcx> for LvalueTy<'tcx> {
 102     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
 103         match *self {
 104             LvalueTy::Ty { ty } => LvalueTy::Ty { ty: ty.fold_with(folder) },
 105             LvalueTy::Downcast { adt_def, substs, variant_index } => {
 106                 LvalueTy::Downcast {
 107                     adt_def: adt_def,
 108                     substs: substs.fold_with(folder),
 109                     variant_index: variant_index
 110                 }
 111             }
 112         }
 113     }
 114
 115     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
 116         match *self {
 117             LvalueTy::Ty { ty } => ty.visit_with(visitor),
 118             LvalueTy::Downcast { substs, .. } => substs.visit_with(visitor)
 119         }
 120     }
 121 }
 122
 123 impl<'tcx> Lvalue<'tcx> {
 124     pub fn ty<'a, 'gcx>(&self, mir: &Mir<'tcx>, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> LvalueTy<'tcx> {
 125         match *self {
 126             Lvalue::Local(index) =>
 127                 LvalueTy::Ty { ty: mir.local_decls[index].ty },
 128             Lvalue::Static(ref data) =>
 129                 LvalueTy::Ty { ty: data.ty },
 130             Lvalue::Projection(ref proj) =>
 131                 proj.base.ty(mir, tcx).projection_ty(tcx, &proj.elem),
 132         }
 133     }
 134 }
 135
 136 impl<'tcx> Rvalue<'tcx> {
 137     pub fn ty<'a, 'gcx>(&self, mir: &Mir<'tcx>, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Ty<'tcx>
 138     {
 139         match *self {
 140             Rvalue::Use(ref operand) => operand.ty(mir, tcx),
 141             Rvalue::Repeat(ref operand, ref count) => {
 142                 let op_ty = operand.ty(mir, tcx);
 143                 let count = count.as_u64(tcx.sess.target.uint_type);
 144                 assert_eq!(count as usize as u64, count);
 145                 tcx.mk_array(op_ty, count as usize)
 146             }
 147             Rvalue::Ref(reg, bk, ref lv) => {
 148                 let lv_ty = lv.ty(mir, tcx).to_ty(tcx);
 149                 tcx.mk_ref(reg,
 150                     ty::TypeAndMut {
 151                         ty: lv_ty,
 152                         mutbl: bk.to_mutbl_lossy()
 153                     }
 154                 )
 155             }
 156             Rvalue::Len(..) => tcx.types.usize,
 157             Rvalue::Cast(.., ty) => ty,
 158             Rvalue::BinaryOp(op, ref lhs, ref rhs) => {
 159                 let lhs_ty = lhs.ty(mir, tcx);
 160                 let rhs_ty = rhs.ty(mir, tcx);
 161                 op.ty(tcx, lhs_ty, rhs_ty)
 162             }
 163             Rvalue::CheckedBinaryOp(op, ref lhs, ref rhs) => {
 164                 let lhs_ty = lhs.ty(mir, tcx);
 165                 let rhs_ty = rhs.ty(mir, tcx);
 166                 let ty = op.ty(tcx, lhs_ty, rhs_ty);
 167                 tcx.intern_tup(&[ty, tcx.types.bool], false)
 168             }
 169             Rvalue::UnaryOp(UnOp::Not, ref operand) |
 170             Rvalue::UnaryOp(UnOp::Neg, ref operand) => {
 171                 operand.ty(mir, tcx)
 172             }
 173             Rvalue::Discriminant(ref lval) => {
 174                 let ty = lval.ty(mir, tcx).to_ty(tcx);
 175                 if let ty::TyAdt(adt_def, _) = ty.sty {
 176                     adt_def.repr.discr_type().to_ty(tcx)
 177                 } else {
 178                     // Undefined behaviour, bug for now; may want to return something for
 179                     // the `discriminant` intrinsic later.
 180                     bug!("Rvalue::Discriminant on Lvalue of type {:?}", ty);
 181                 }
 182             }
 183             Rvalue::NullaryOp(NullOp::Box, t) => tcx.mk_box(t),
 184             Rvalue::NullaryOp(NullOp::SizeOf, _) => tcx.types.usize,
 185             Rvalue::Aggregate(ref ak, ref ops) => {
 186                 match **ak {
 187                     AggregateKind::Array(ty) => {
 188                         tcx.mk_array(ty, ops.len())
 189                     }
 190                     AggregateKind::Tuple => {
 191                         tcx.mk_tup(
 192                             ops.iter().map(|op| op.ty(mir, tcx)),
 193                             false
 194                         )
 195                     }
 196                     AggregateKind::Adt(def, _, substs, _) => {
 197                         tcx.type_of(def.did).subst(tcx, substs)
 198                     }
 199                     AggregateKind::Closure(did, substs) => {
 200                         tcx.mk_closure_from_closure_substs(did, substs)
 201                     }
 202                 }
 203             }
 204         }
 205     }
 206 }
 207
 208 impl<'tcx> Operand<'tcx> {
 209     pub fn ty<'a, 'gcx>(&self, mir: &Mir<'tcx>, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Ty<'tcx> {
 210         match self {
 211             &Operand::Consume(ref l) => l.ty(mir, tcx).to_ty(tcx),
 212             &Operand::Constant(ref c) => c.ty,
 213         }
 214     }
 215 }
 216
 217 impl<'tcx> BinOp {
 218       pub fn ty<'a, 'gcx>(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
 219                     lhs_ty: Ty<'tcx>,
 220                     rhs_ty: Ty<'tcx>)
 221                     -> Ty<'tcx> {
 222         // FIXME: handle SIMD correctly
 223         match self {
 224             &BinOp::Add | &BinOp::Sub | &BinOp::Mul | &BinOp::Div | &BinOp::Rem |
 225             &BinOp::BitXor | &BinOp::BitAnd | &BinOp::BitOr => {
 226                 // these should be integers or floats of the same size.
 227                 assert_eq!(lhs_ty, rhs_ty);
 228                 lhs_ty
 229             }
 230             &BinOp::Shl | &BinOp::Shr | &BinOp::Offset => {
 231                 lhs_ty // lhs_ty can be != rhs_ty
 232             }
 233             &BinOp::Eq | &BinOp::Lt | &BinOp::Le |
 234             &BinOp::Ne | &BinOp::Ge | &BinOp::Gt => {
 235                 tcx.types.bool
 236             }
 237         }
 238     }
 239 }
 240
 241 impl BorrowKind {
 242     pub fn to_mutbl_lossy(self) -> hir::Mutability {
 243         match self {
 244             BorrowKind::Mut => hir::MutMutable,
 245             BorrowKind::Shared => hir::MutImmutable,
 246
 247             // We have no type corresponding to a unique imm borrow, so
 248             // use `&mut`. It gives all the capabilities of an `&uniq`
 249             // and hence is a safe "over approximation".
 250             BorrowKind::Unique => hir::MutMutable,
 251         }
 252     }
 253 }
 254
 255 impl BinOp {
 256     pub fn to_hir_binop(self) -> hir::BinOp_ {
 257         match self {
 258             BinOp::Add => hir::BinOp_::BiAdd,
 259             BinOp::Sub => hir::BinOp_::BiSub,
 260             BinOp::Mul => hir::BinOp_::BiMul,
 261             BinOp::Div => hir::BinOp_::BiDiv,
 262             BinOp::Rem => hir::BinOp_::BiRem,
 263             BinOp::BitXor => hir::BinOp_::BiBitXor,
 264             BinOp::BitAnd => hir::BinOp_::BiBitAnd,
 265             BinOp::BitOr => hir::BinOp_::BiBitOr,
 266             BinOp::Shl => hir::BinOp_::BiShl,
 267             BinOp::Shr => hir::BinOp_::BiShr,
 268             BinOp::Eq => hir::BinOp_::BiEq,
 269             BinOp::Ne => hir::BinOp_::BiNe,
 270             BinOp::Lt => hir::BinOp_::BiLt,
 271             BinOp::Gt => hir::BinOp_::BiGt,
 272             BinOp::Le => hir::BinOp_::BiLe,
 273             BinOp::Ge => hir::BinOp_::BiGe,
 274             BinOp::Offset => unreachable!()
 275         }
 276     }
 277 }